Flow controlling device for refrigerating systems



Sept. 29, 1936. D. RNEWMAN FLOW CONTROLLING DEVICE FOR REFRIGERATINGSYSTEMS Filed Jan. 18, 1936 Figi L Inventor":

Patented Sept. 29, 1936 UNITED sTATEs PATENT OFFICE FLOW CONTROLLINGDEVICE FOR REFRIGERATING SYSTEMS New York AppllcationJanuary 18, 1936,Serial No. 59,739 6 Claims. (Cl. 138-42) My invention relates to flowcontrolling devices for controlling the flow of refrigerant between thehigh and low pressure sides of refrigerating systems.

It has heretofore been proposed to utilize long capillary tubes having acomparatively small inside diameter to maintain the required differencein pressure between the high and low pressure sides of a refrigeratingsystem. Such a device must be arranged to restrict the flow of vaporizedrefrigerant from the high pressure side of the system to the lowpressure side thereof, while at the same time permitting the flow ofsufllcient liquid refrigerant therethrough to meet the capacityrequirements of the system at the lowest pressure difference prevailingbetween the high and low pressure sides of the system during the normaloperation thereof. Although such capillary tubes are simpler and moreeconomical to construct than the float valves or other devices havingmoving parts, which have heretofore been used as flow controllingdevices between the high and low pressure sides of refrigeratingsystems,

such capillary tubes are nevertheless bulky and' susceptible to damagesince such a tube may be easily crushed thus shutting off the flow ofrefrigerant therethrough and rendering the refrigerating systeminoperative.

It is an object of my invention to provide a flow controlling device forcontrolling the flow of refrigerant between the high and low pressuresides of a refrigerating system which comprises an improved arrangementof sheet metal parts that are economical to manufacture, the flowcontrolling device being effective in operation and rugged inconstruction.

Further objects and advantages of my invention will become apparent asthe following description proceeds and the features of novelty whichcharacterize my invention will be pointed out with particularity in theclaims annexed to and forming a part of this specification.

For a better understanding of my invention, reference may be had to theaccompanying drawing in which Fig. 1 is a side elevation, partly insection, of a refrigerating machine provided with a flow controllingdevice embodying my invention; Fig. 2 is a perspective view of the flowcontrolling device of the refrigerating machine shown in Fig. 1; Fig. 3is a developed view of the flow controlling device shown in Figs. 1 and2, portions of the flow controlling device being broken away in order tobetter illustrate the internal construction thereof; Fig. 4 is asectional view along the line 4-4 of the new controlling device shown inFig. 3;

Fig. 5 is a developed view of a modified form of fiow controllingdevice, embodying my invention, which may be used in the refrigeratingmachine shown in Fig. 1, and Fig. 6 is a sectional view along the line6-6 of the flow controlling device shown in Fig. 5. I

Referring to the drawing, I have shown in Fig. 1 a refrigeratingmachine, designed for household use, which includes a motor drivencompressor unit contained in a cylindrical hermetically sealed casingIll-mounted on the upper side'of a removable heatinsulated top wall I Iof the refrigerator cabinet in which the refrigerating machine is used.Compressed vaporized refrigerant, such as sulphur dioxide, is suppliedfrom the compressor contained in the casing ID to a cylindrical sheetmetal condenser I2 which surrounds the casing I0 and is mounted thereon.The compressed gaseous refrigerant thus supplied to the condenser I2circulates through a helical refrigerant circulatory passage I3 formedin the condenser I2 and is liquefied by the transfer of heat therefromto the cooling air which circulates over the surfaces of the condenser.The cooling air circulates up- ,wardly over the surfaces of thecondenser I2 and between the condenser and the casing I0 by naturaldraft. The refrigerant thus liquefied in the condenser I2 flows througha conduit I 4 to a cylindrical receiver I5 which is mounted on'the wallII. Liquid refrigerant accumulated in the receiver I5 flows therefromthrough a conduit I6 -to a flow controlling device I! embodying myinvention and is supplied therefrom through a liquid line I8 to aflooded type sheet metal evaporator I9.

The evaporator I9 is supported on the lower side of the wall [I in arefrigerator cabinet food storage compartment, the contents of which isto be cooled. The evaporator I9 is provided with a plurality ofrefrigerant circulatory passages 20 which communicate with alongitudinal cylindrical header 2| below the normal liquid leveltherein. The header 2| is maintained about half full of liquidrefrigerant and the refrigerant circulatory passages 20 are thus floodedwith liquid refrigerant. The liquid refrigerant contained in theevaporator I9 is vaporized by the absorption of heat from thecompartment in which the evaporator is located and the refrigerant thusvaporized is collected in the header 2I above the level of the liquidrefrigerant therein. The vaporized refrigerant thus collected in theheader 2| is returned to the compressor in the casing I0 through asuction conduit 22 which communicates with the header 2| above thenormal liquid level therein. This cycle is repeated and continued untilthe temperature of the compartment in which the evaporator I9 is locatedis reduced to the desired value.

The flow controlling device |1 includes an elongated substantiallyrectangular sheet of metal 23 and complementaryrectangular sheets ofmetal 24 and 25, which are arranged on opposite sides of the sheet ofmetal 23 and conform thereto throughout their length. The sheets ofmetal 23, 24, and 25 are preferably made of cold-rolled steel. Arelatively narrow elongated zigzag slot is formed in the sheet of metal23. This elongated slot preferably includes a plurality of transverseslots 26 arranged in substantially parallel relation. These slots 26 areconnected in series relation by a plurality of longitudinal slots 21arranged at the alternate opposite ends thereof and extending betweenthe adjacent end portions of the transverse slots 26. It will be notedthat the longitudinal slots 21 communicate with the transverse slots 26intermediate the'ends thereof, so that small recesses or pockets 28,arranged in alignment with the adjacent portions of the transverse slots26, are formed at the opposite ends of the latter. Since the recesses 28are located adjacent the reentrant bends formed-in the zigzag or sinuousfluid passage composed of the slots 26 and 21, the recesses serve toincrease the turbulence of any vaporized refrigerant as it flows fromthe slots 26 to the slots 21 or from the slots 21 to the slots 26. Boththe slots 26 and 21 are of relatively small cross section in order torestrict or substantially prevent the flow of vapor therethrough. Theslots 26 and 21 are preferably about .001 square inch in cross sectionalarea when the flow controlling device is used with a refrigeratingmachine having a capacity of about 550 B. t. u.s per hour, using sulphurdioxide as a refrigerant, and operating in. an ambient temperature of F.The provision of a flow controlling device for controlling thev flow ofrefrigerant between the high and low pressure sides of a refrigeratingsystem and comprising a member having a plurality of fluid passagesformed therein and arranged in substantially parallel relation, and anarrangement including a plurality of connecting passages formed in saidmember for connecting the fluid passages in series relation, theconnecting passages being arranged at alternate opposite ends of thefluid passages and communicating with adjacent end portions thereofintermediate the ends of said fluid passages is not my invention, but isthe invention of Christian Steenstrup and is described in his copendingapplication Serial No. 59,756, filed January 18, 1936, and assigned tothe General Electric Company, the assignee of my present invention.

The sheet of metal 25 is preferably of the same peripheral dimensions asthe sheet of metal 23, while the sheet of metal 24 is. somewhat widerthan the sheets 23 and 25. The longitudinal edges 29 and 30 of the sheet24 are folded over the adjacent longitudinal edges of the sheets 23 and25 and the sheets are brazed or otherwise hermetically sealed together.Complementary semi-cylindrical indentations 3| and 32 are formed in thesheets of metal 24 and 25, respectively, at adjacent ends thereof. Theindentations 3| and 32 are tightly fitted around the lower end of theconduit l6 and are brazed or otherwise. hermetically sealed thereto. Oneof the slots 26, located at an end of the series of such slots,communicates with the complementary indentations 3| and 32. A similarpair of complementary semi-cylindrical indentations 33 and 34 are formedin the sheets of metal 24 and 25, respectively, and communicate with theone of the slots 26 located at the opposite end of the series of suchslots. These indentations 33 and 34 are tightly fitted on the upper endof the liquid line l8 being brazed or otherwise hermetically sealed.thereto and thus forming an outlet for the flow controlling device l1.

In making the flow controlling device H described above, the slots 26and 21 as well as the recesses or notches 28 are punched or otherwiseformed in the sheet of metal 23. The complementary indentations 3|, 32,33, and 34 are stamped or otherwise formed in the flat sheets of metal24 and 25. The sheets of metal 24 and 25 are then arranged in facecontact with the sheet of metal 23 on opposite sides thereof and in suchposition that they conform with each other throughout substantiallytheir entire lengths. The edges 29 and 30 of the sheet of metal 24 arethen folded over the adjacent edges of the sheets of metal 23 and 25.The sheets of metal 23, 24, and 25 are then brazed together throughoutthe area of the contacting surfaces thereof or are otherwisehermetically secured together. After having been thus secured togetherthe sheets of metal 23, 24,and 25 are then wound into a helical form,their finished shape being illustrated in Fig. 2. Thermal insulation 35is arranged between adjacent layers of the helically wound sheets ofmetal in order to prevent the transfer of heat between bodies ofrefrigerant passing through the fluid passage made up of the slots theadjacent portions of the flow controlling device. The flow controllingdevice |1 thus formed is preferably mounted in the heat insulation ||aof the refrigerator cabinet wall I.

It will thus be seen that the slots 26,21, and 28, formed in the sheetof metal 23, cooperate with the adjacent portions of the sheets of metal24 and 25 to form an elongated sinuous or zigzag flow controllingrefrigerant passage of sufficient length and sinuosity as compared toits cross sectional area substantially to'prevent the flow of vaporizedrefrigerant therethrough, while permitting the quantity of liquidrefrigerant to flow therethrough required by the capacity of the systemat the lowest pressure difference existing between the high and lowpressure sides of the system during the normal operation thereof. Thepockets or recesses 28 are particularly useful in preventing the flow ofvaporized refrigerant through the sinuous fluid passage formed by theslots 26 and 21 in that the turbulence of the vapor which changesdirection of flow at the junctions between the slots 26 and 21 isincreased by the 'recesses 28 into which a portion of the vapor flows.That is, when the vapor flows along the slots 26, for example, it tendsto continue in the same direction of flow and thus enters the recesses28. Upon striking the closed ends of the recesses 28, the vapor reboundsand turbulenbe therein results. This turbulence is, of course, increasedas the speed of movement of the fluid is increased. When liquidrefrigerant is flowing through the sinuous fluid passage formed by theslots 26 and 21, however, much I less turbulence is set up therein bythe recesses 28 in view of the fact that the liquid ordinarily flows ata slower speed than the vapor flowing through the fluid passage and,consequently, the

turbulence set up in the liquid upon a change in 26 and 21 in directionof its flow is less than in the case of the vapor. The flow controllingdevice, which I have illustrated, is compact and rugged and may bereadily manufactured from sheet metal by well known and economicalmanufacturing operations. It is particularly desirable to form therefrigerant passage in the flow controlling device by slots in a sheetof metal rather than by indentations in a sheet of metal, for example,because the shearing die ordinarily used in forming the slots is lesssubject to wear than a compression or stamping die. a sheet of metal aresubject to variations in size because of differences in the granularstructure or thickness of the metal. Hence, the slots are of moreuniform size than would be indentations.

When the slotted sheets of metal 23 are handled and especially when theyare handled in large quantities during factory production thereof, theymay become twisted or skewed, that is, the longitudinal edges of theslotted sheets 23 may be moved lengthwise relative to each other so thatsome of the slots 26 and 21 are narrowed and others are widened thusmaterially changing their resistance to the flow of fluids therethrough.In Figs. 5 and 6, I have shown a modified form of flow controllingdevice Ila, embodying my invention, which is very similar to the flowcontrolling device ll described above but in which this difficulty isobviated.

The flow controlling device Ila includes an elongated substantiallyrectangular sheet of metal 23a and complementary rectangular sheets ofmetal 24a and 25a which are arranged on opposite sides of the sheet ofmetal 23a andconform thereto throughout their length. The

' sheets of met-a1 23a, 24a, and 250. are preferably made of cold-rolledsteel. A series of relatively narrow elongated zigzag slots are formedin the sheet of metal 23a. These elongatedslots preferably include aplurality of transverse slots 26a arranged in substantially parallelrelation.

Groups of these slots 26a are connected in series relation by aplurality of longitudinal slots 21a arranged at the alternate oppositeends thereof and extending between the adjacent end portions of thetransverse slots 2601.. It will be noted that the longitudinal slots 21acommunicate with the transverse slots 26a intermediate the ends thereofso that small recesses or pockets 28a, arranged in alignment with theadjacent portions of the, transverse slots 26a, are formed in theopposite ends of the latter. Since the recesses 28a are located adjacentthe reentrant bends formed in the zigzag or sinuous fluid passagescomposed of the slots 26a and 21a, the recesses serve to increase theturbulence of any vaporized refrigerant as it flows from the slots 26ato the slots 21a or from the slots 21a to the slots 26a. Both the slots26a and 21a are of relatively small cross section in order to restrictor substantially prevent theflow of vapor therethrough. The slots 26aand 21a are preferably about .001 sq. in. in cross sectional area whenthe flow controlling device is used with a refrigerating machine havinga capacity of about 550 B. t. u.s per hour, using sulphur dioxide as arefrigerant, and

operating in an ambient temperature of F.

Moreover, indentations made inand described above, except that some ofthe connecting slots 21 in the sheet 23 are omitted in the sheet 23a.Consequently, the sheet 23a is much more rigid than the sheet 23 and isnot likely to be skewed or twisted during handling. The sheet of metal25a is preferably of the same peripheral dimensions as the sheet 230,while the sheet 24a is somewhat wider than the sheets 23:; and 25a. Thelongitudinal edges 29a and 30a of the sheet 24a are folded over theadjacent longitudinal edges of the sheets 23a and 25a. and the sheetsare brazedor otherwise hermetically sealed together. The plurality ofzigzag passages formed by the slots 26a and 21a are connected in seriesrelation by a plurality of indentations 24b formed in the sheet of metal24a. These indentations 24b connect the adjacent end portions of theslots 26a intermediate their ends and extend across the unslotted portions 23b of the sheet of metal 23a.-

Complementary semi-cylindrical indentations 3la and 32a are formed inthe sheets of metal 24a and 25a, respectively, at the adjacent endsthereof. The indentations 3la and 32a are adapted to be fitted aroundthe lower end of the conduit 16 shown in Fig. l and may be brazed orotherwise hermetically sealed thereto. One of the slots 250, located atone, end of the series of such slots communicates with the complementaryindentations 3la and 32. A similar pair of complementarysemi-cylindrical inden- Ila. After the sheets of metal 23a, 24a, and

25a have been secured together as described above they are preferablybent into a compact helix.

It will thus be seen that the flow controlling device Ila is formed ofrelatively rigid parts i which may be easily handled during themanufacture thereof without danger of injuring the same. Also the slots26a and 21a may be formed by a. shearing die in the sheet of metal 23aand, as a consequence, will have relatively uniform dimensions. Althoughthe indentations 24b in the sheet of metal 24a. form a part of the fluidpassage through the flow controlling device Ila, they constitute only avery minor part of the total length thereof. formed in the sheet ofmetal 241; will not have such uniform dimensions as a slot, for example,because of the inherent limitations, referred to above, of the stampingapparatus ordinarily used in producing such indentations. This variationin the dimensions of the indentations 24b will not, however, materiallyaifect the flow charac- The indentations 24b teristics of the fluidpassage formed in the flow controlling device Ila since the totaloverall length of the indentations 24b is small as compared to theoverall length of the slots 26a and 21a.

While I have shown two particular embodiments of my invention inconnection with a compression type refrigerating machine, especiallydesigned for household use, I do not desire my invention to be limitedto the particular construction shown and described and I intend in theappended claims to cover all modifications within the spirit and scopeof my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is:

1. A flow controlling device for controlling the flow of refrigerantbetween the high and low pressure sides of a refrigerating systemcomprising a portion of sheet metal having an elongated relativelynarrow slot formed therein, complementary portions of sheet metal,arranged on opposite sides of said slotted portion of sheet metal andconforming thereto substantially throughout their length, and means forhermetically securing all of said portions of sheet metal together, saidsecond named portions of sheet metal closing the sides of said slot andcooperating therewith to form an elongated fluid passage.

2. A flow controlling device for controlling the flow of refrigerantbetween the high and low pressure sides of a refrigerating systemcomprising aportion of sheet metal having an elongated zigzag relativelynarrow slot formed therein, complementary portions of sheet metalarranged on opposite sides of said slotted portion of sheet metal andconforming thereto substantially throughout their length, and means forhermetically securing all of said portions of sheet metal together, saidsecond named portions of sheet metal closing the'sides of said zigzagslot and cooperating therewith to form an elongated fluid passage.

3. A flow controlling device for controlling the flow of refrigerantbetween the high and low pressure-sides of a refrigerating systemcomprising an elongated substantially rectangular sheet of metal havinga relatively narrow zigzag slot formed therein, complementarysubstantially rectangular sheets of metal arranged on opposite sides ofsaid slotted sheet of metal in face contact therewith and conformingthereto substantially throughout their length, the longitudinal edges ofone of said being folded over the adjacent longitudinal edges of theother sheets of metal, and means for hermetically securing all of saidsheets of metal together, said second named sheets of metal closing thesides ofv said slot and cooperating therewith to form an elongated fluidpassage.

4. A flow controlling device for controlling the flow of refrigerantbetween the high and low pressure sides of a. refrigerating systemcomprising an elongated substantially rectangular sheet of metal having'a plurality of transverse slots formed therein and arranged insubstantially last named sheets of metal.

parallel relation, said sheet of metal having longitudinal slots thereinarranged at alternate opposite ends of said transverse slots andextending between adjacent end portions thereof, said longitudinal slotscommunicating with said transverse slots intermediate the ends thereof,complementary rectangular sheets of metal arranged on opposite sides ofsaid slotted sheet of metal in face contact therewith and conformingthereto substantially throughout their length, and means forhermetically securing all of said sheets of metal together, said secondnamed sheets of metal closing the sides of said slots and cooperatingtherewith to form an elongated fluid passage.

5. A flow controlling device for controlling the flow of refrigerantbetween the high and low pressure sides of a refrigerating systemcomprising a portion of sheet metal having a plurality of elongatedrelatively narrow slots formed therein, complementary portions of sheetmetal arranged on opposite sides of said slotted portion of sheet metaland conforming thereto substantially throughout their length, means forhermetically securing all of said portions of sheet metal together, saidsecond named portions of sheet metal closing the sides of said slots andcooperating therewith to form a plurality of elongated fluid passages,and means including a plurality of indentations formed in at least oneof said second named portions of sheet metal and extending betweenadjacent portions of said slots for connecting said elongated fluidpassages in series relation.

6. A flow controlling device for controlling the flow of refrigerantbetween the high and low pressure sides of a refrigerating systemcomprising a portion of sheet metal having a plurality of elongatedzigzag relatively narrow slots formed therein, complementary portions ofsheet metal arranged on opposite sides of said slotted portion of sheetmetal and conforming thereto substantially throughout their length,means for hermetically securing all of said portions of sheet metaltogether, said second named portions of sheet metal closing the sides ofsaid zigzag slots and cooperating therewith to form a plurality ofelongated fluid passages, and means including a plurality ofindentations formed in at least one of said second named portions ofsheet metal extending between adjacent portions of said slots forconnecting said elongated fluid passages in series relation.

' DELBERT 'F. NEWMAN.

